The waste water from food processing contains dissolved salts and organic matter. The amount of each depends upon the product being processed and the procedure being used. The suitability for irrigation of food processing waste water from 20 plants processing nine food products was assessed from the standpoint of electrical conductivity (EC), chloride and sodium concentrations, sodium-adsorption-ratio (SAR), and chemical oxygen demand (COD). Waste water from plants processing green beans (Phaseolus vulgaris L.), squash (Cucurbita pepo var. melopepo Alef.), tomatoes (Lycopersicon esculentum Mill.), corn (Zea mays L.), steam peeled potatoes (Solanum tuberosum L.) and sweet potatoes (Ipomoea batatas Lam.), and poultry is suitable for irrigation under most conditions. Waste water from some pea (Pisum sativum L.) and lima beans (Phaseolus lunatus L.) processing plants may be suitable for irrigation, but is of questionable suitability from others. Waste water from lye-peel potato processing is not suitable for irrigation.

An interval-stochastic-fuzzy policy analysis model is proposed to generate optimal security management policy for a water–energy–food nexus system of the urban agglomeration under multiple uncertainties. A number of planning policies under interval-stochastic surface water and groundwater conditions are obtained. Ranking scores of all policies in descending order, policy with the highest score is the best choice. Results disclose that (a) interval-stochastic available water resources lead to changing system benefits. (b) The shares of cropland area targets are 2.7% (Xiamen), 42.6% (Zhangzhou), and 54.7% (Quanzhou). (c) Different available water scenarios result in varied irrigation patterns. (d) Surface water takes a high fraction of the total water supply (about [71.34, 73.68]%), diesel agricultural machinery service more than 60% of the total cropland. (e) Zhangzhou contributes about 50.01% of total TN and TP emissions, while Quanzhou contributes about 50.61% of total carbon emission. (f) Security level of policies would change with the varied σ and α values, due to the risk attitudes of policy makers. (h) Sweet potato and others are the crops with the highest safety performance; (i) Zhangzhou is the city with highest comprehensive safety performance.